Multiple opposed piston engine



0d 31, 1944- s. B. MATHls MULTIPLE OPPOSED PISTON ENGINE Filed April 9, 1943 "3 Sheets-Sheet 1 S. as

m Ilm INVENTOR. BY ceu/@M7105 MULTIPLE OPPOSED PISTON ENGINEA Filed Apri19. 1943 5 Sheets-Sheet 2 INVENTOR. .Tceur /J 7er/n.7

Oct. 31, 1944. s B, MA1-HisV 1 `2,361,70

MULTIPLE OPPOSED PISTON VENGINE Filed April 9, 1943 3 Sheets-Sheet 3 INVENTOR. 66mm/ /Yflr/f/.S

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Patented Oct. 3.1, 1944J UNITED STATES PATENT OFFICE I f MULTIPLE oPPosEp PI'sToN ENGINE scanf mms, Memphis, Tenn'.- Application April'9, 1943, Serial No. 482,409 (c1. 12a- 51) by a key 25, to a power shaft 21 which extends 2 Claims.

This invention relates to improvements in four cycle internal combustion engines, and particularly to an internal combustion engine having a cylinder, or cylinders, in which is, or are, mounted a pair, or pairs, of pistons coordinated to move synchronously in opposite directions, and to the means for coordinating these opposite movements, and delivering the power therefrom.

The primary objects of the invention are:

To increase the effective length of expansion stroke; i r- To greatly simplify the cylinder construction by eliminating therefrom any head or heads;

To coordinate and ,synchronize the movement of each opposed pair of pistons and transfer the torque of the two crank shafts for such pistons to a joint power shaft;

To simplify the valve construction, by reducing the number of valves to an intake valve and an exhaust valve for each pair of pistons; and

To simplify and reduce the valve operating mechanism by utilizing a one to two gear relation between the crank shafts and the power shaft, thereby establishing a half time speed of the power shaft, and utilizing the power shaft as the half time cam shaft.

The means by which the foregoing and other objects are accomplished, and the manner of their accomplishment, will readily be understood from the following specification upon reference to the accompanying drawings, in which:

Fig. l is a sectional elevation taken on the line I-I of Figs. 2 and 3.

Fig. 2 is a corresponding plan; and

Fig. 3 is a transverse sectional elevation taken on the line III-III of Fig. 1.

Referring now to the Adrawings in which the various parts are indicated by numerals:

In its preferred form, I I is a base on which oppositely disposed side frames I3, I5, of substantial identity, are mounted, these frames including flanges I3-A, I5-A respectively, which are secured to the base II.. The frames are spaced apart to house a main gear I1, and a pair of driving gears I9 and! I, which mesh with ther main gear, the pitch lines of these gears being indicated in Fig. 1. The frames may be provided with peripheral flanges I3-B, Fig. 3, extended inward into abutting relation and secured together rigidly by bolts 23, the flanges I 3-B,

I-B peripherally enclosing the gears I1, I9 and 2l. The gears i9 and 2| are of identical diameter and are of one-half the diameter of the main gear.

The main gear is mounted on and secured as transversely through the side frames and is journalled as in hubs'29 extending laterally from the frames. 3i are flywheels.

The driving gears are mounted on and secured as by keys (not shown) respectively to shafts 31 and 39, which serve as crank shafts for the opposite ends of the engine cylinders and are hereinafter designated as crank shafts,v the crank.

shafts also extending transversely through the side frames and being respectively journalled as in hubs 4I and 43 carried by the frames.

symmetrically disposed on opposite sides of the gear housing between the crank shafts 31 and 39, and respectively integral with or rigidly secured to the side frames I3, I5 are cylinders 45 and 41, having parallel axes which intersect the axes of the crank shafts in usual manner. These cylinderseach consists of a'single elongated barrel, without intermediate head, each of theopposite ends of the barrel functioning as a cylinder.

Mounted in the cylinder 45 are a pair of pistons 4,9 and 5I and in the cylinder 41 a similar pair of pistons 53 and 54. The pistons of each cylinder, as the pistons 49 and 5I, of cylinder 45, are disposed in the cylinder, head to head in oppositely faced relation, and are connected in usual manner through piston pins 55, and connecting rods 51 to crank pins 59 and 6I respectively carried by crank discs 63 and 65 on the crank shafts 31 and 39, the pistons of the opposite cylinder 41 being similarly connected to crank pins 61 and 69 carried by crank discs 1I and 13 on the opposite ends of the same crank shafts 31 and 39;

The crank pins 59 and 6I are so positioned that both pistons 49 and 5l are on the inner or outer, as the case may be, dead center at the same time, and the crank pins 61, 69 similarly relatively so positioned, but preferably at one hundred and eighty degrees from the crank pins 59 and 6I The cylinders 45 and 41 are provided with valve boxes 15 and 11 respectively, in which are mounted, as in the valve box 15, for cylinder 45, an inlet valve 19, and an exhaust valve 8|, the inlet valve 19 being operated by a cam 83 and the exhaust valve 8| by an adjacent cam 85 through rocker arms 81 and 89 respectively, and the valves for the opposite cylinder 51 being similarly operated. 'Ihe cams 83 and 85 are mounted on and keyed, or otherwise secured, to the power shaft 21, and the cams for the cylinder 41 similarly secured to the same shaft on the opposite side of the frames.

The two valve boxes 15 and 11 are provided with exhaust pipes 93 and 95 respectively, and are also connected through a suitable manifold 91 to a carburetor 99. IUI, |03 are spark plugs which are timed and energized in usual and well known manner.

The lpistons, as the pistons I9, I, mounted in cylinder 45, approach on the instroke, but are provided with suitable clearance to form a combustion chamber, as at |05, Fig. 1, the wall of the cylinder being cut away within the valve box 'l5 to leave a connectingopening L01 for the pasfsage of combustion gases from the valve box into the cylinder, and reversely of exhaust gases from the cylinder into the valve box. 1

It will readily be understood that one cylinder and its associated pistons'and working parts only may be used, though the preferred structure includes the two cylinder construction shown.

It will also be understood that unless the power shaft is to be used as a halftime cam shaft, there need be no particular ratio between the driving gears and the main gear, but that irrespective of this ratio and the gear sizes, the two driving gears must be of .equal diameter. Idler gears may be introduced between the driving gears and the main gear in the usual manner of gear trains.

It is preferred that the power shaft be above the cylinders, but it may be below, as would happen by inversion of the structure, and it may be moved closer to the cylinders by reduction of gear diameters, or further therefrom by increase of their diameters or by insertion of idler gears. The cylinder barrel may b e a single elongated barrel or two half length barrels secured together end to end.

It will also be understood that the term crank disc as used in the claims is inclusive of the term crank arm.

I claim:

1'. In an internal combustion engine, a Ibase, a spaced pair of plate-like frame members secured to said base and extendingvertically upward therefrom, hubs extending in opposite horizontal directions from said frame members, a power shaft at right angles to said frame members.

journalled in said hubs and projecting oppositely therefrom, additional hubs in pairs extending krespectively Vin opposite directions from said members, and spaced equally below and equally outfor said gears, andv bolts securing said anged members together to form thereof a frame; a pair of assemblies, disposed respectively on opposite sides of said frame, each assembly comprising an elongated cylinder barrel carried by said frame and axially alined between said crank shafts, a pair of pistons disposed in opposed relation in opposite end portions of said cylinder barrel, and connecting rod-crank assemblies respectively operatively coupling said pistonsl and said crank shafts; a valve chamber mounted on said cylinder and communicating thereinto between said pistons at innerdead center, intake and exhaust valves, carried by said chamber and controlling now to and from said cylinders, and an intake cam, and an exhaust cam, carried by said power shaft, and rocker arms carried by said frame,

` respectively interposed betwen said intake cam and .intake valve, and said exhaust cam and exhaust valve.

2. In an internal combustion engine, a base, a spaced pair of plate-like frame members secured to said base and extending vertically upward therefrom, hubs extending in opposite horizontal directions from said frame members, a power shaft at right angles to said frame members, journalled in said hubs and projecting oppositely therefrom, additional hubs in pairs extending respectively in opposite directions from said members, and spaced equally below and equally outward from said first hubs, and a pair of crank shafts parallel to, and equally spaced from, said power shaft, extending through, journalled in and projecting from said additional hubs, a pair of driving gears of equal diameters secured respectively on said crank shafts, and a main gear of twice said driving gear diameter, secured on said power shaft and meshing with said driving gears,

` all said gears being disposed between said frame members, said members above said base having each a peripheral ange, said flanges extending into abutting relation to form a housing for said gears, andbolts securing said anged memibers together to form thereof a frame; an engine assembly comprising an elongated cylinder barrel disposed along and carried by said frame and ward from said rst hubs, and a pair of crank shafts parallel to, and equally spaced from, said power shaft, and projecting from said additional hubs, a pair of driving gears of equal diameters secured respectively on said crank shaftsfand a main gear of twice said driving gear' diameter, secured on said power. shaft and meshing with said driving gears, all said gears being disposed between said frame members, said members above said base having each a peripheral ange, said anges extending into abutting relation, to form a housing extending through, journalled in axially alined between said crank shafts, a pair of pistons disposed in opposed relation in opposite end portions of said cylinder barrel, and connecting rod-crank assemblies respectively operatively coupling said pistons and said crank shafts; a valve chamber mounted on said cylinder and communicating thereinto between said pistons at inner dead center, intake and exhaust valves, carried by said chamber and controlling ow to and from said cylinders, an intake cam. and an exhaust cam, carried by said power shaft, and rocker arms carried by said frame, respectively interposed between said intake cam and intake valve, and said exhaust cam and exhaust valve.

SCALLY B. MATHIS. 

